Showing papers in "Copeia in 1940"

Delayed Fertilization in Leptodeira annulata polysticta

Abstract: A FEMALE specimen of Leptodeira annulata polysticta Giinther, taken from a bunch of bananas in March, 1934, in Detroit, Michigan, and presumably from Central America, came into my possession in August of that year. This snake, the only one of its species in my possession, is still living. It has been kept continuously in a small cage, isolated from other snakes. It has thriven in captivity, feeding on lizards and frogs, and growing from 750 mm., when captured, to 960 mm. at the present time. The fact that this specimen, long isolated from any contact with a male, has continued to lay fertile eggs contributes evidence on what appears to be a problem of broad biological importance. On March 20, 1936, a clutch of seven eggs was found in the cage. They were in a shrunken condition, indicating that they had been laid several days previous to their discovery. They were thin-shelled, leathery in texture, and uniformly light creamy white in color, and when inflated with 10 per cent formalin were found to average 28.9 x 12 mm. in size. In one of the eggs a small red area was seen through the shell but this disappeared after preservation.

Food of the Long-Nosed Gar (Lepisosteus osseus oxyurus) and the Bowfin (Amia calva) in Southern Michigan

Abstract: GARS and bowfins are classed as "noxious fishes" in Michigan and as such are often removed from sport-fishing waters. The data here presented were gathered in order to obtain a preliminary idea as to whether or not such control might be justified. Comparison of these results with those of other investigators and conclusions regarding the economic status of these predatory fishes, however, are reserved until further studies have been completed.

The Rate of Growth of the Northern Pike, Esox lucius Linnaeus, in Wisconsin Waters

Abstract: ITHIN recent years the trend in fishery biology has been toward Vfish management, with particular emphasis on lake improvement. Construction and artificial fertilization of lakes and ponds and selected planting of various species of fish are giving investigators some idea of the specific requirements of each species. To make an analysis of the influence of various factors in the environment upon its fish population, it is necessary to study the rate of growth of a species in one environment, and then to make comparisons with the same species under another set of conditions.

Correct Terminology in Salamander Myology II. Transverse Ventral Throat Musculature

Abstract: The larvae of all salamanders have four superficial transverse ventral throat muscles. In the adults there may be either three or four, depending on the species. The prevailing terms-and those which are the only logical ones from the standpoint of comparative anatomy and embryology-are: intermandibularis anterior, intermandibularis posterior, interhyoideus, interhyoideus posterior, inter-ossaquadrata, quadrato-pectoralis, subhyoideus, and gularis. It remains only to demonstrate the proper allocation of these terms among the various urodele genera. In the larvae of all salamanders the most anterior, small, and occasionally indefinite muscle without a median raphe is the intermandibularis anterior. In the Proteidae, Necturidae, Amphiumidae, Cryptobranchidae, and Sirenidae this muscle persists throughout life. There may be occasional exceptions to this, but they are individual aberrancies and not differences between species. In the remaining families, Hynobiidae, Ambystomidae, Salamandridae, and Plethodontidae, the intermandibularis anterior disappears completely at metamorphosis. In these last four families, then, the most anterior muscle in the metamorphosed adult is the intermandibularis posterior. The fact that this latter muscle is very often subdivided into a number of separate slips has caused some confusion, and the entire muscle has very often been erroneously called the intermandibularis anterior by some writers, including the author (Piatt, 1935). According to Eaton (1936: 49) the accountgiven by Hoffmann (1873-1878: 95) is the best source of information concerning the presence of the intermandibularis anterior in urodeles. Hoffmann's brief account is inadequate and definitely wrong. A more detailed and very accurate paper on this subject is the one by Luther (1914). It has been shown (Edgeworth, 1911, 1935; Piatt, 1938) that the transverse throat muscles posterior to the intermandibularis posterior arise in the early salamander embryo as a single mass of mesoderm derived from the fusion of the ventral portions of the hyoid arches. Later the mass splits into an anterior interhyoideus and a posterior interhyoideus posterior. Both these muscles are maintained throughtout life in all salamanders, but with certain definite changes in different genera. Those species in which metamorphosis occurs normally and in which the interhyoideus and interhyoideus posterior remain unaltered are the Cryptobranchidae, Amphiumidae, and Ambystomidae. In these families the larval interhyoideus and interhyoideus posterior are carried over into the adult animal unchanged, save for a slight shifting of

The Races of Ambystoma tigrinum

Abstract: sion that it was not possible to subdivide the general population of Ambystoma tigrinum on structural characters. I am of the same opinion, after examining much more material than was available to him. I further think that bicolor, conspersum, copeianum, trisruptum, and xiphias, which he recognized on structural characters, and of each of which he had only a very few specimens, are conspecific with tigrinum. Four of these appeared in the 1917 edition of the Check List, but were dropped, on my insistence, in the edition of 1923.